1. Technical Field
This invention relates generally to locking methods and apparatus, and in particular to a locking device to prevent theft of a removable pickup truck tailgate.
2. Background Art
Pickup truck tailgates are usually hinged at the bottom of the tailgate so as to permit rotation of the tailgate from a lockable closed vertical position to one in which the truck bed is open. In addition, such tailgates may be easily removed from the truck in order to facilitate such functions as backing up to a loading platform. Since locking means are conventionally provided to secure the tailgate in the closed position only, removable tails may be easily stolen after they are opened.
This problem has been recently addressed in several inventions. For example, Bowman, in U.S. Pat. No. 4,981,320 provides mechanical means for preventing normal removal of the side links which support a horizontal open tailgate door. Since such links are usually connected to a bolt-head type stud on the truck body through variably sized slot openings in the link, fastening means are provided which will internally occlude the larger portion of the slot opening necessary for removal of the stud head. The fastening means however, are secured to the strap by bolts or rivets. Since the former may be easily removed by owner and thief alike, and the latter with more difficulty by both, security is only obtained if the feature of a removable tailgate is given up.
In a different approach, U.S. Pat. No. 5,004,287 to Doyle discloses apparatus in which an elongated hingepin member may be extended from the truck body into a receiving cup located in the tailgate. An opening in the side wall of the receiving cup permits normal removal of the door. Lateral movement of lock bolt may be accomplished by either an electrical solenoid or through the rotary motion of a cylinder lock. Although the lock bolt housing, lock bolt, and lock may alternatively be mounted in the truck body with the receiving mechanism built into the tailgate, either approach requires considerable mechanical modification to both existing truck members.
A need still exists therefore, for a simple locking device which can be installed by anyone who can remove a removable tailgate from a truck without the need to alter the existing truck or tailgate design by mechanical modification.